XXX. Responsibility and Qualification of Locomotive Runners 544 List of Books for Mechanics, Locomotive Runners, Firemen, etc., 550 Plates 551 APPENDIX. I. Table of the Properties of Steam 585 II. Table of Hyperbolic Logarithms 590 III. Table of the Properties of Different Kinds of Fuel 594 IV. Table of the Resistance of Trains 596 Index 598 INTRODUCTION. The Catechism of the Locomotive is intended for a large class of readers, among whom are all kinds of railroad officers and employes, consisting of locomotive runners, firemen, and the many different kinds of mechanics employed in railroad shops and in the construction of locomotive and other kinds of railroad machinery and material. Besides these there are many amateur engineers, students, and persons interested directly or indirectly in railroads, and a not inconsiderable class who are always seeking information on all subjects whatsoever. It is evident, therefore, that the only way to adapt the book to all the classes for whom it is intended, was to make it so plain that the “wayfaring man” will have no difficulty in comprehending it. It has therefore been written in as clear language as the writer could command, and the subjects presented are treated as simply and as plainly as his ability enabled him to do, and with the least possible employment of either scientific or practical technicalities. The only deviation from this plan will be found in the use of algebraic symbols to designate arithmetical calculations. This was done to save space, and because it was thought that they could be explained so that even those without any knowledge whatsoever of algebra could easily comprehend them. To such as have no such knowledge the following explanation is given: Suppose it is necessary to add two numbers, say 1,872 and 468. The calculation, if made arithmetically, would be thus: 1,872 468 ----- 2,340 This it will be seen occupies the space of several lines of print. If we want to express this calculation algebraically, it can be done by simply writing the two numbers and placing the sign +, called _plus_, between the two, which indicates that they are to be added together, thus: 1,872 + 468 To indicate what the _sum_ will be, or what the two added together will amount to, the sign =, called _equal to_, or the sign of equality, is placed after the two numbers and between them and the sum, thus: 1,872 + 468 = 2,340, which can be read as follows: 1,872 _added to_ 468 _is equal to_ 2,340.